Quantifying Variation in the Seed Scatter-hoarder Relationship

The relationship between scatter-hoarders and trees varies on a continuum from mutualism to antagonism and can change across time, location, and among species. We examined five tree species across five sites to quantify this variability: red oak (Quercus rubra), white oak, (Quercus alba), American chestnut (Castanea dentata), Chinese chestnut (Castanea mollissima), and a hybrid American/Chinese chestnut. In the fall of 2012, 2013, and 2015, we set up field sites across the east coast, including in Virginia, Pennsylvania, Indiana, Massachusetts, and Maine. We tested the potential for mutualism between scatter-hoarders and trees by using a simple model proposed in the literature that compares rates of seedling emergence with and without scatter-hoarders. The model uses the ratio of seed emergence from the surface divided by seed emergence from a cache (Es/Ec) as one variable to place seeds on a continuum from mutualism to antagonism. We predicted across different study sites and found that that red oak seeds will have a more mutualistic relationship with scatter-hoarders because of their long dormancy period before germination, white oak seeds will have an antagonistic relationship because they germinate readily, and chestnuts will fall in between. We hypothesized that abiotic conditions surrounding the seed would have a stronger influence on the Es/Ec ratio than the provenance of the seed would. We found that different seed provenances caused variation in the Es/Ec ratio, but abiotic conditions described more of the variation in the continuum from mutualism to antagonism. We also quantified the effect of temperature at our different study sites to measure the correlation between temperature and emergence. We found that temperature did not predict the high degree of variation in the effect of abiotic conditions on the degree of mutualism

Measuring microsatellite conservation in mammalian evolution with a phylogenetic birth-death model.

Microsatellites make up ∼3% of the human genome, and there is increasing evidence that some microsatellites can have important functions and can be conserved by selection. To investigate this conservation, we performed a genome-wide analysis of human microsatellites and measured their conservation using a binary character birth--death model on a mammalian phylogeny. Using a maximum likelihood method to estimate birth and death rates for different types of microsatellites, we show that the rates at which microsatellites are gained and lost in mammals depend on their sequence composition, length, and position in the genome. Additionally, we use a mixture model to account for unequal death rates among microsatellites across the human genome. We use this model to assign a probability-based conservation score to each microsatellite. We found that microsatellites near the transcription start sites of genes are often highly conserved, and that distance from a microsatellite to the nearest transcription start site is a good predictor of the microsatellite conservation score. An analysis of gene ontology terms for genes that contain microsatellites near their transcription start site reveals that regulatory genes involved in growth and development are highly enriched with conserved microsatellites

Calcium and the effects of grugs on smooth muscles of the oesophagus of Aplysia brasiliana (Mollusc-Opistobranch)

Movimentos expontâneos do esôfago de Aplysia brasiliana apresentam dois tipos de contração: tônicas ou sustentadas e fásicas. Ambos os tipos são afetados pelo teôr de Calcio++ na água do mar. Ação da ACh sôbre a musculatura do esôfago deste Gastrópode - Opistobrânquio também depende diretamente do teôr de Calcio++ no líquido perfusor que é da ordem de 0.020 g/l. As reações do órgão a diferentes salinidades foram estudadas e discutidas

Uncovering the Mechanism of Aggregation of Human Transthyretin.

The tetrameric thyroxine transport protein transthyretin (TTR) forms amyloid fibrils upon dissociation and monomer unfolding. The aggregation of transthyretin has been reported as the cause of the life-threatening transthyretin amyloidosis. The standard treatment of familial cases of TTR amyloidosis has been liver transplantation. Although aggregation-preventing strategies involving ligands are known, understanding the mechanism of TTR aggregation can lead to additional inhibition approaches. Several models of TTR amyloid fibrils have been proposed, but the segments that drive aggregation of the protein have remained unknown. Here we identify β-strands F and H as necessary for TTR aggregation. Based on the crystal structures of these segments, we designed two non-natural peptide inhibitors that block aggregation. This work provides the first characterization of peptide inhibitors for TTR aggregation, establishing a novel therapeutic strategy

Dyslipidaemia and Undernutrition in Children from Impoverished Areas of Maceió, State of Alagoas, Brazil

Chronic undernutrition causes reduced growth and endocrine adaptations in order to maintain basic life processes. In the present study, the biochemical profiles of chronically undernourished children were determined in order to test the hypothesis that chronic undernutrition also causes changes in lipid profile in pre-school children. The study population comprised 80 children aged between 12 and 71 months, including 60 with moderate undernutrition [height-for-age Z (HAZ) scores ≤ −2 and > −3] and 20 with severe undernutrition (HAZ scores ≤ −3). Socioeconomic, demographic and environmental data were obtained by application of a questionnaire, and anthropometric measurements and information relating to sex, age and feeding habits were collected by a trained nutritionist. Blood samples were analysed for haemoglobin, vitamin A, insulin-like growth factor 1 (IGF-1) and serum lipids, while cortisol was assayed in the saliva. Faecal samples were submitted to parasitological investigation. Analysis of variance and χ2 methods were employed in order to select the variables that participated in the multivariate logistic regression analysis. The study population was socioeconomically homogeneous, while the lack of a treated water supply was clearly associated with the degree of malnutrition. Most children were parasitised and anaemia was significantly more prevalent among the severely undernourished. Levels of IGF-1 decreased significantly with increasing severity of undernutrition. Lipid analysis revealed that almost all of the children had dyslipidemia, while low levels of high-density lipoprotein were associated with the degree of undernutrition. It is concluded that chronic malnutrition causes endocrine changes that give rise to alterations in the metabolic profile of pre-school children

Charge redistribution at Pd surfaces: ab initio grounds for tight-binding interatomic potentials

A simplified tight-binding description of the electronic structure is often necessary for complex studies of surfaces of transition metal compounds. This requires a self-consistent parametrization of the charge redistribution, which is not obvious for late transition series elements (such as Pd, Cu, Au), for which not only d but also s-p electrons have to be taken into account. We show here, with the help of an ab initio FP-LMTO approach, that for these elements the electronic charge is unchanged from bulk to the surface, not only per site but also per orbital. This implies different level shifts for each orbital in order to achieve this orbital neutrality rule. Our results invalidate any neutrality rule which would allow charge redistribution between orbitals to ensure a common rigid shift for all of them. Moreover, in the case of Pd, the power law which governs the variation of band energy with respect to coordination number, is found to differ significantly from the usual tight-binding square root.Comment: 6 pages, 2 figures, Latex; Phys.Rev. B 56 (1997

Association between malnutrition in children living in favelas, maternal nutritional status, and environmental factors

OBJECTIVE: To investigate the association of malnutrition in children living in substandard settlements (slums) of Maceió, AL, Brazil, with maternal nutritional status and environmental conditions. METHODS: Cross-sectional study involving a probability sample of 2,075 mothers (18 to 45 years) and their children (4 months to 6 years), living in the slums of the city of Maceió. First, we conducted a cluster analysis with the purpose of choosing the settlements and the administrative region of the city of Maceió with the lowest human development index. After this analysis, the 7th Administrative Region was designated for the study, including its 23 substandard settlements. Socioeconomic, demographic, anthropometric, and maternal and child health data were collected by means of household survey. The statistical analysis included the odds ratio of a child to be malnourished, and the univariate regression was used to check which maternal variables were associated with this malnutrition. RESULTS: Chronic malnutrition (-2 standard deviations/height for age) was found in 8.6% of children and was associated with mother's age and educational level, type of residence, number of rooms, flooring, water supply, and low birth weight (< 2,500 g) in children aged < 24 months. We also found an association between child malnutrition and maternal height. Such association was not observed regarding body mass index. CONCLUSIONS: The high prevalence of malnutrition observed in these settlements was related to social and environmental conditions and short maternal height, who had weight deficit or weight excess.OBJETIVO: Investigar a associação da desnutrição em crianças residentes em assentamentos subnormais (favelas) de Maceió (AL) com o estado nutricional materno e as condições socioambientais. MÉTODOS: Estudo transversal, envolvendo amostra probabilística de 2.075 mães (18 a 45 anos) e respectivos filhos (4 meses a 6 anos), moradoras nas favelas da cidade de Maceió (AL). Para escolha dos assentamentos, procedeu-se primeiramente a uma análise de clusters para eleger a região administrativa da cidade de Maceió com menor índice de desenvolvimento humano. Após essa análise, a 7ª Região Administrativa foi a designada para o estudo, com seus 23 assentamentos subnormais. Os dados socioeconômicos, demográficos, antropométricos e de saúde materno-infantil foram coletados através de inquérito domiciliar. A estatística analisou a razão de chances de uma criança ser desnutrida, e a regressão univariada foi usada para verificar quais variáveis maternas estariam associadas a essa desnutrição. RESULTADOS: A desnutrição crônica (-2 desvios padrão/altura por idade) esteve presente em 8,6% das crianças e associou-se com idade e escolaridade materna, tipo de residência, número de cômodos, revestimento de piso, origem da água e baixo peso ao nascer (< 2.500 g) em crianças com idade < 24 meses. Encontrou-se também associação entre desnutrição infantil e baixa estatura materna, que não foi observada para índice de massa corporal. CONCLUSÕES: A alta prevalência de desnutrição infantil observada nesses assentamentos esteve relacionada às condições socioambientais e à baixa estatura das mães, que apresentaram déficit ou excesso de peso.Secretaria Estadual de Saúde de AlagoasUniversidade Federal de Alagoas Faculdade de NutriçãoUniversidade Federal de São Paulo (UNIFESP) Departamento de FisiologiaUNIFESP, Depto. de FisiologiaSciEL

A Time-Tested Information System in Neurosurgical Oncology

The Brain and Spine Center at The University of Texas MD Anderson Cancer Center is a leading multidisciplinary referral center for patients with nervous system (NS) tumors. It has a wealth of clinical experience and an internationally recognized leadership role in the management of NS cancers. In that context, an informatics infrastructure that allows the archiving of both the prospective and retrospective characterization of patients, diseases, treatments, and outcomes is invaluable. We describe our experience with the Neurosurgical Oncology Database, a database that has provided valuable, extensive, and readily searchable data on multifaceted patient, tumor, and treatment characteristics for many years, successfully serving as an administrative and operational resource and as a resource for retrospective and prospective research endeavors